Transforming apparatus



June 25, 1940.

R. B. HUNTER 'IRANSFORMING APPARATUS Filed Jan. 23, 1939 Patented June 25, 1940 UNITED STATES PATENT OFFICE Cutler-Hammer, Inc., Milwaukee,

poratlon of Delaware Wia, a cor- Application January 23, 1939, Serial No. 252,264

11 Claims.

This invention relates to transforming apparatus for supplying energy from a constant voltage source to a translating circuit at variable voltage. The invention is particularly applicable 5 to transformers provided with means for commutating a winding thereof and adapted to be connected to a three-wire constant voltage sup- V p1y and to supply a three-wire load circuit or one or a plurality of two-wire load circuits with 10 a variable voltage.

An object of the invention is to provide a transformer having two winding sections ar-v ranged on a common magnetic core and having means to connect them in series.

Another object is to provide a transformer 02 the aforementioned type, having separate regu-' lating means for each winding, said regulating means being so arranged that they may be operated simultaneously to provide equal output voltages for the two windings.

Another object is to provide a transformer of the aforementioned type which may be alternatively connected to different types of load sys-= tems.

Another object is to provide apparatus of the aforementioned character wherein the trans-= former is of the autotronsiormer whereby the voltages supplied to a plurality of: oael circuits will be maintained cf hire or equal values notwithstanding inequality or", or in the relative values or", the loads in said lead circ ts Another and mo e specific object is to provide "d which articula ly the illun atlonin 35 alsity control pl" r of lamp circmts, l "i119 ve circuits are supplied with L l are i intly intensity cc.

0" er obi I a as ted to former embodying the invention and connected to a three-wire supply and to a three-wire load circuit, and

Fig. 2 shows a transformer connected to a three-wire supply circuit and to two separate 5 two-wire load circuits.

Referring to Fig. 1, the transformer is providedwith a ring-shaped closed magnetic core ltwhich preferably consists of a stack of annular laminations, but which may also be built up in any other suitable manner. The two halves of the core I have wound thereon. windings 2 and 3, respectively; the two windings being wound in opposite directions, so as to be symmetrical with respect to each other. The turns of the windlogs are insulated from each other and from the core l, but are bared of insulation on the outer perimeter of the transformer. A pair of contact brushes 5 and 5 respectively are mounted on arms El and 5, respectively, and are arranged to ll contact the bare portions of the wires at the. periphery of the windings at diametrically opposed points of the two windings. The arms 6 and l are insulatedly fastened to opposite ends of a lever which is rotatable about a pvot 9 at the center of the ring 6 and which lever may he connected to suitable operating means in any desired manner.

"Une pair ill and ll of the diametrically opposed of the two windings are connected toether form a common point which in turn is onnectetl to the neutral wire L or a source constant voltage; the other wires L and 1. of said source being connected to oi windings 2 and 3, respectively. hus the'wlnding" and 3 connected in series ohe the outer wires and L of the three :e system and 'mduce the core l fluxes which are cumulative. the pivot 29 and on arms J are to two aicecl sectors and 53, respectively, and stationary crushes l5 and :15 are adapted con tact lever 8 rotates. A three== wire load its outer wires L L to the brushes and t5, respectively, 5 viii n utral w e L is connected to the e windings and and to Thus as the lever is rced both sides of the load circuit are supplied 13h equal voltages which vary simultaneously minim to a ma: mum as the lever is rotated clockwise from the entreme counterclocle wine position to clockwise position there n.

limes-ring to 22, the same former having a ring-shaped core I similar to the core of the transformer shown in Fig. 1. A winding 20 which is divided by a center tap 2! into two equal halves is wound on the core and is connected by its end terminals to the lines L and L respectively, of a three-wire supply line, while the center tap 2i is connected to the center or neutral wire of said line. The two halves of the winding!!! are wound on the core in the same direction. The turns of the wires are bared of insulation on the outer perimeter of the transformer to make contact with the brushes 24 and 25, respectively, at diametrically opposite points of the transformer. A lamp circuit is connected between the lines L L which are electrically connected to the line L and to the brush 35, respectively while a second lamp circuit is connected between the lines L L which are electrically connected to the lines L and to the brush 34, respectively. The brushes 24 and 25 are connected through the lever sections 26 and 21 (carried by but insulated from the central lever section. 28) to the brushes 34, and 35, respectively. As the lever 28, upon the sections 26 and 21 of which the brushes 24 and 25 are mounted, is rotated, equal portions of the winding 2d are connected across the respective lamp circuits to provide them with equal variable voltages.

The drawing illustrates the use of the invention as applied to an autotransformer, but it is obvious that a two-coil transformer having separate primary and secondary windings may be employed.

The connection of the brushes 4 and 5 and 24 and 25, respectively, to the load circuit-may be accomplished by other means than those shown in Fig. 1 or 2', and instead of arranging said brushes to contact directly with the individual wires of the windings, separate contacts which in turn are electrically connected to different points on the windings may be provided for engagement by the brushes. It is further possible, if desired, to connect the supply wires in Fig. l to the brushes 4 and 5 and the load wires to the winding ends in and II, in which case the relationship of the line and load voltages will be reversed with respect to thataforedescribed.

' Other modifications will readily'suggest themselves to those skilled in the art.

What I claim as new and desire to secure by Letters Patent is:

1. An alternating current transformer comprising, a ring-shaped magnetizable core, two symmetrical windings on said core and connected and arranged cumulatively relatively to the core for connection across a three-wire snpply'circult, and a pair of contact brushes movable simultaneously and adapted to connect equal variable sections of said windings across a load circuit.

2. An alternating current transformer comprising, a substantially closed magnetizable core, two symmetrical windings inductively related to.

said core and "connected and arranged cumula-'v tively relatively to said core for connection across a three-wire supply circuit, a movable contact brush for each winding including means to connect a variable number of turns of each winding across a load circuit, and means to move said brushes simultaneously so as to maintain the numbers -of turns of both windings which are in circuit alike.

3. An. alternating current transformer comprising, a ring-shaped magnetizable core, two

wires of said windings on the outer perimeter oi. the transformer being providedwith contact surfaces, a contact carrier oscillatable about the center of said core, and two contact brushes car- I ried by said carrier, one for each winding, and

adapted to contact diametrically opposite surfaces of the respective windings as the carrier is moved, said brushes being provided with means to connect them across a load circuit.

4. An alternating current transformer comprising, aring-shaped magnetizable core, two windings on said core and connected in series across the outer wires of a three-wire supply circuit, while their common center is connected to the neutral wire of said circuit, the wires of said windings on the outer perimeter of the transformer being provided with contact surfaces, a contact carrier oscillatable about the center of said core, and two contact brushes carried by said carrier, one for each' winding, and adapted to contact diametrically opposite surfaces of the respective windings as the carrier is moved, said brushes being provided with means to connect them across a load circuit. F

5. An alternating current transformer comprising,- a ring-shaped magnetizable core, two windings on said core, said windings being-provided with contact surfaces forming one group for each winding and arranged concentric with said core and corresponding to certain turns of said windings in the natural order of the turns thereof, and a pair of contact brushes movable about'the center of said core and adapted to connect equal variable sections of said windings across a load circuit.

6. An alternating current transformer comprising a substantially closed magnetizable core, two windings inductively related to said core, said windings being adapted to be connected in series to a three-wire single phase circuit, having a neutral terminal, a contact brush for each winding, individual means to connect a translating circuit between said neutral terminal and said brush, and means to complete the circuit between said brush and a variable section of the corresponding winding.

7. An alternating current transformer comprising a substantially closed magnetizable core, two windings inductively related to said core, means to connect one winding between one side and the neutral terminal of a three-wire circuit I and to connect the other winding between the other side and said neutral terminal, a contact brush for each winding, means to connect a load to said brushes, and means to complete a circuit between said brushes and equal variable sections of the corresponding windings respectively.

8; In an illumination control system, the combination with a lamp circuit, of a transformer comprising, a ring-shaped magnetizable core,

two symmetrical windings on said core and connected and arranged cumulatively relatively to the latter for connection across a three-wire supply circuit, and a pair of contact brushes adapted to connect equal variable sections of said windings across said lamp circuit.

9. In an illumination control system, the combination with a lamp circuit, of a transformer comprising,'a substantially closed magnetizable core, two. symmetrical windings inductively related to said core and connected and arranged cumulatively relatively to said core for connection across a three-wire supply circuit, a movable contact brush for each winding including means to connect a variable number of turns of each winding to a load circuit, and means to move said brushes simultaneously so as to maintain the numbers of turns of both windings which are in circuit alike.

10. In an illumination control system, the combination with a lamp circuit, of a transformer comprising a substantially closed magnetizable core, two windings inductively related to said core, said windings being arranged to bev connected in series to a three-wire, single-phase circult, having a neutral terminal, a contactbrush for each winding, means to connect said lamp circuit to said neutral terminal and said brushes, and means to complete the circuit between said brushes and variable sections of the correspond ll. In an illumination intensity control systen, in comblnatioma pluralityoi. groups of 3 electric lamps, a three-wire source oi current supply, an autotransiormer comprising a ringshaped magnetizable core, two windings inductively associated with said core and electrically connected with each other and with said source '5 of current supply in a manner to provide for cumulative action thereof relatively to said core, a pair of oscillatable contact brushes for said windings, said brushes being electrically connected with the respective groups of lamps to 1 provide for connection of a variable number of turns of the respective windings in circuit with their associated groups of lamps, and means to effect joint oscillatory movement of said brushes. to thereby maintain of equal value the number 1 of turns of the respective windings which are included in circuit.

RICHARD B. HUNTER. 

